The demand in recent years for wide-screen displays with an image quality typified by high-vision has seen much research directed into cathode ray tube (CRT), liquid crystal display (LCD), and plasma display panel (PDP) technologies. CRTs are widely used in televisions and the like for their high resolution and image quality, although the large increases in device depth and weight that accompany increases in screen size mean that CRTs having a diagonal screen size exceeding 40 inches are not considered feasible.
LCDs by far exceed CRTs in terms of reduced energy consumption, device depth, and weight, and are now widely used as computer monitors, although the intricate construction of thin film transistors (TFT), the most common type of LCD, means that the manufacturing process is very involved. Increases in screen size consequently lead to a drop in yield rates, making the manufacture of LCDs over 20 inches not as yet feasible.
The attraction of PDPs, on the other hand, is the ability to combine a wide screen with a comparatively lightweight display. Increasing the screen size of PDPs has thus been a focus in the push to develop the displays of the future, and already available on the market are products having a diagonal screen size in excess of 60 inches.
PDPs are a type of gas discharge panel comprising two facing glass substrates, the inner surface of one of the glass substrates including plural pairs of display electrodes arranged in strips across a plurality of barrier ribs. Phosphors corresponding to the colors red, green, and blue are applied in order in the gap between adjacent barrier ribs, one color per gap, respectively, and the space between the two glass substrates is sealed. Phosphor illumination is then generated by discharging ultraviolet light (UV) within the discharge space, which is the sealed space between the two glass substrates and the interposed barrier ribs.
Direct current (DC) and alternating current (AC) are the two types of PDPs, distinguished by the power source used to drive them. AC PDPs, generally recognized as the most suitable for wide-screen application, are fast becoming the norm.
Due to contemporary demands for energy efficient electrical appliances, much of the interest in PDP development has centered on reducing the energy taken to drive them. This focus is particularly emphasized given the rise in energy consumption resulting from recent trends toward developing PDPs with larger screens and higher image definition.
One means of reducing the energy consumption of PDPs is to improve the illuminance efficiency, although measures that simply aim to cut the electricity supplied to PDPs are not viable because of resultant drops in illumination and display capacity caused by a reduction in the discharge capacity generated between the pairs of display electrodes. Improving the rate at which the phosphors change ultraviolet light into visible light is one way in which improvements in illuminance efficiency are being pursued, although much work still needs to be done in this area.
The issues discussed above relate not only to PDPs and other gas discharge panels but also to gas discharge devices (i.e. devices providing illumination by generating a discharge within a glass vessel filled with a discharge gas). The present difficulties in developing gas discharge panels and gas discharge devices lie, therefore, in securing a favorable discharge capacity while sustaining the illuminance efficiency.